Many cities are built in seismically active areas in which earthquakes or other seismic activity occur from time to time.
When a significant seismic event does occur it is necessary for existing buildings and other structures to be checked to confirm how the structure has reacted, whether it is in need of repair, how urgently any repairs are required, and whether it can continue to be used in the meantime.
Although the seismic activity of most areas is recorded on a macro scale, for example by government operated seismic monitoring stations, the accelerations experienced by a particular building may be influenced by the local geology, the design and construction of the building, and other factors.
In assessing the safety and performance of a particular building it would be of benefit to have a record of the actual accelerations (magnitude and direction) experienced by the building. In the case of particularly large or tall structures it would be desirable to have information from several parts of the structure, for example from different floors of multi-storey buildings.
The prior art contains examples of apparatus for detecting and recording the effect of seismic activity on such structures. However, these tend to be large and expensive items of equipment which often require attention after each seismic event recorded, and which cannot operate for extended periods without some form of maintenance. As a result, such apparatus are not widely used at present.
As well as seismic activity, other forces such as high winds, heavy traffic, explosions, and in some cases pedestrian activity, may cause movement in a structure which needs to be recorded and analysed in order to confirm that the structure is safe, or to identify parts of the structure which require repair.
The reference to any prior art in the specification is not, and should not be taken as, an acknowledgement or any form of suggestion that the prior art forms part of the common general knowledge in any country.
It is accordingly an object of the present invention to provide an apparatus and/or system for detecting and recording accelerations experienced by a structure and/or a method of operating such apparatus, which will overcome or ameliorate problems with such methods and/or apparatus at present, or which will at least provide a useful choice.
Further objects of the present invention may become apparent from the following description, which is given by way of example only.